| 摘要 |
A method for manufacturing a ring-shaped magnet material, the method comprising: in a penetrating hole formed in a die, arranging a mandrel having a cylinder tip portion of a diameter d<SUB>1</SUB>, a cylinder base end portion of a diameter d<SUB>2 </SUB>(provided d<SUB>1</SUB><D<SUB>2</SUB>), and a taper portion of a taper angle theta<SUB>2 </SUB>positioned between the cylinder tip portion and the cylinder base end portion; loading the cylinder tip portion with a preform from which a ring-shaped magnet material is made, the preform being a circular-ring column shaped body whose inner diameter is d<SUB>1</SUB>; and plastic-working the preform in a gap, which the penetrating hole and the mandrel form, by pressing the preform with a pressing punch whose inner diameter is d<SUB>1 </SUB>and whose outer diameter is the same as that of the penetrating hole, the manufacturing method providing more freedom for design with respect to the magnetic properties and allowing the ring-shaped magnet material having excellent magnetic properties and high dimension accuracy to be manufactured continuously with high yield. |
